1. Field of the Invention
The present invention relates to a glass antenna which may be employed for, e.g., a radio set for personal radio communications service or a car telephone system which is mounted on an automobile, as an antenna which serves for both transmission and reception in the UHF band (300 to 3,000 MHz). More particularly, the present invention pertains to a glass antenna formed on the surface of glass mounted on a vehicle such as a window glass.
2. Description of the Related Art
One type of antenna which utilizes the surface of glass has already been put into practical use as an antenna employed exclusively for reception in the VHF band. Since this type of antenna has a relatively low gain and an unfavorably large VSWR (voltage standing-wave ratio), it has heretofore been impossible to apply such an antenna to the UHF band in a simple way and for both transmission and reception.
For this reason, it is general practice to adopt vertical rod antennas for equipment for personal radio communications service (service band: 903 to 905 MHz) and car telephones mounted on automobiles.
Rod antennas which project outward from the bodies of automobiles involve the following problems: hindrance to washing and garaging of the cars; the fear of rod antennas being stolen or broken; the noise generated by such antennas when the automobile is moving and the adverse effect on the external appearance of the cars.